The invention discloses wall protecting mud for pile pulling of a pressure bearing sand layer and a preparation method thereof. The wall protecting mud for the pile pulling of the pressure bearing sand layer is prepared from the following raw materials in parts by weight: 6.5 to 21.5 parts of bentonite, 0.45 to 0.55 part of sodium carbonate, 0.18 to 0.22 part of sodium carboxymethylcellulose, 0.045 to 0.055 part of fatty alcohol-polyoxyethylene ether, and 100 parts of water. The preparation method comprises the following steps: weighing the bentonite, the sodium carbonate, the sodium carboxymethylcellulose, the fatty alcohol-polyoxyethylene ether and the water in proportion; mixing, stirring and puffing to obtain the wall protecting mud for the pile pulling of the pressure bearing sand layer. The wall protecting mud for the pile pulling of the pressure bearing sand layer has a good effect on separating a pile from a wall and protecting the wall; the pile pulling quality is high.